Ignition magneto



J. R. STARK.

IGNITION MAGNETO.

APPLICATION FILED AUG-25, 1920.

Patented Feb. 21, 1922.

3 SHEETS-SHEET 1.

J. R. STARK.

IGNITION MAGNETO.

APPLICATION FILED AUG.25, 1920. 1,407,099, Patented Feb. 21, 1922.

3 SHEETS-SHEET 2- [J6 mew 3.! 5 1 J0]??? E J'Z/" J. R. STARK.

IGNITION MAGNETO.

APPLICATION FILED AUG-25. 1520.

1,407,099, Patented Feb. 21, 1922 3 SHEETS-SHEET 3 UNITED STATES PATENT OFFICE.

JOHN ROY STARK, OF RACINE, WISCONSIN, ASSIC'NOR 'IO WEBSTER ELECTRIC COMPANY, OF RACINE, WISCONSIN, A CORPORATION OF WISCONSIN.

IGNITION MAGNETO.

Specification of Letters Patent.

Patented Feb. 21, 1922.

Application filed August 25, 1920. Serial No. 405,957.

To all, whom it may concern:

Be it known that 1' JOHN ROY STARK, a citizen ofthe United states, and resident of Racine, in the county of Racine and State of Wisconsin, have invented a certain new and useful Improvement in Ignition Magnetos,

of which the following is a full, clear conover-all length of the magneto 'is reduced to a minimum, at the same time providing am ple bearingsurface for the armature trunnions. The over-all length of the particular magnetoconstruction herein shown is quite small but the armature trunnion bearings are nevertheless considerably larger than the bearings which are quite generally employed in connection with machines of even greater length.

At the present time the rather limited space for ignition magnetos on the engines with which they are emplo ed, has created a demand for magnetos 0 small size and particularly of small over-all length. In meeting this requirement, manufacturers of ignition magnetos have quite generally resorted to the expedient of reducing the length of the armature trunnion bearings. This expedient is not good practice-because unless the armature trunnion bearings are sufficiently long, no magneto will operate sat is'factorily for any considerable length of time. I have found that thebest practice requires that the armature trunnion bearings should be even larger than those commonly employed heretofore. With these considerations in mind, I have evolved a magneto construction comprisin-gextremely long armature trunnion bearings, which bearings, however, are so disposed that the lie in space from which the bearings have been excluded in prior magneto constructions, enablin me materially to reduce the over-all lengt of the machine despite the fact'thatl have increased the length of the armature trunnion beari Other objects of the invention will appear as the.f0l.1 WiI1g detail description prog s s.

the several parts of which are so I disc 19 of In the accompanying drawings illustratmg myinvention,

Figure 1 is a vertical sectional view of a ,magneto embodying the improvements of my invention.

F lgure 2 1s a rear elevational view thereof with a portion of the cap associated with the removable end plate broken away.

Figure 3 is a top plan view of the magneto. Figure 4 is a. front elevational view thereof.

Figure 5 is a vertical sectional view taken on the line 5-5 of Figure 1, and

Figure 6 is a fragmentary sect ibnal view indicating the manner in which the distributor spool is attached to its associated armature disc.

Similar characters of reference refer to similar parts throughout the several views.

The magneto shown comprises field magnet 10 and the field frame or magneto housing 11, the latter being provided with suitable pole pieces, not shown, which pole piecesmay be of any suitable construction but are preferably of the type shown and described in my co-pending application, Case 10, Serial No. 405,959, filed of even date herewith.

One end of the housing 11 is formed integral therewith and is provided with a hollow inwardly projecting boss 12 which constitutes a bearing for one of the armature trunnions. The other end of the housing is closed by the removable end plate 13 which. is provided with an inwardly projecting hollow boss 14 which constitutes an armature trunnion hearing. The plate 13 is provided at its upper portion with an opening 15 to afford ready access to the interrupter mechanism presently to be described. The opening 15 is normally closed by a cap 16 which is held cin position by a leaf spring 17. One

end of the spring 17 is firmly held under the head of one of the screws wherewith plate 13 is fastened to the housing ll'while the free end of spring 17 bears against the outer end of a pin 18. The pin'18 projects through the cap 16 and has its inner end attached to a good conducting material. The disc 19 co-operates with a spring-pressed plunger 20 which is carried in a recess in the adjacent armature trunnion. This lunger 20, disc 19, pin 18 and spring 1? serve effectively to ground the armature to the magneto framework. It willbe noted that the end plate 13 is provided with a strip of clearly illustrated in Figure 1.

felt indicated at 13 which effectively prevents the ingress of dust between the end plate and the cap.

The armature structure is provided with the trunni0ns 21 and 22 which are respectively journaled in the bearing bosses 12 and 14.

The bearing bosses are preferably pro vided with linings of a material that will Wear well against the steel armature trunnions. These linings are conveniently in the form of brass tubing indicated at 12 and 14. The bearing for armature trunnion 21 is conveniently lubricated from a suitable oil well 23 and the bearing for the trunnion 22 is lubricated from a similar oil well 24.

WVhile the specific construction of the armature is not particularly important so far as my present invention is concerned, I prefer to employ the type of armature shown and described in my co-pending application, Case 9, Serial No. 405,958 filed of even date herewith. This form of armature comprises, in addition to the trunnions 21 and 22, the core 23 carrying primary and secondary windings, the segmental blocks 24 24 which lie at the sides of the ends of the core, and the discs 25 and 26. seen that the trunnions are fixed to the discs 25 and 26 and that these discs, the blocks 24 -s-24 and the core 23 are riveted or otherwise rigidly fastened together. The usual condenser is indicated at 27 and is preferably carried on the inner face of the disc 25.

Disposed immediately adjacent the a1-1na ture disc 26 is the distributor spool 28. This spool is formed of insulating material and is provided with a conducting ring 29. As is clearly shown in Figure 6, the spool 28 is provided with a pair of studs indicated at 30 and 31. These studs fit snugly in the apertures in the disc 26 and are held therein by U-shaped spring clips 3232. These clips engage in annular grooves in the studs and prevent the withdrawal of the studs from the disc 26. It will be noted that stud 31 furthermore constitutes a conduit through which one of the terminals of the secondary winding is lead to the conducting ring 29.

The central opening through spool 28 is substantially greater than the greatest di ameter of the bearing boss 12 so that the spool may lie around the said boss as is 4 It will be noted that there is but a very slight clearance between spool 28 and the adjacent end of the housing. The bearing for trunnion 21 is considerably longer than the trunnion bearings usually found in magnetos of this general type but this exceptionally long trunnion bearing does not necessitate elongation of the magneto as a whole for; the reason that the major portion of the. hearing lies within the spool 28.

It will be- The conducting ring 29 co-operates with a spring-pressed brush 33 carried in the block 34 of any suitable insulating material. Electrically connected with the brush 33 and extending from the block 34 is the high tension lead 35 through which the ignition current is supplied to the spark plug of the engine with which the magneto is associated. The base of the block 34 is preferably rectangular in shape so that the block may be placed in either of two positions in a cor- ,respondingly shaped recess in the top of the housing 11. By virtue of this arrangement, the high tension lead 39 may be caused to project from either side of the magneto. Block 34 is held in position by the free end of a leaf spring 36, the other end of which is clamped to the top of the magneto housing by a suitable screw as illustrated in Figure 1.

My present invention, as herein illustrated, is applied to that type of magneto known in the trade as a high tension oscillator. However, my invention is not limited to use with this particular type of magneto machine. It will be understood, of course, in an adaptation of my invention to a rotary ignition magneto for a multiple cylinder eng1ne,. the spool 28 will be provided wlth adistributor segment which would successively contact with brushes connected with the several spark plugs of the engine in a well-known manner.

I have explained how the distributor devices are grouped around the bearing boss 12. I will now explain how, for a similar purpose, the interrupter devices are distributed around the boss 14. Carried by the disc 25 and insulated therefrom in the usual manner is a plate 37 one end of which is turned at right angles to the plane of the disc to over-lie the bearing boss 14 and is provided with the fixed interrupter contact 38. Plate 37 is, of course, electrically connected with the insulated terminal of the primary winding in the usual manner. The other interrupter contact, indicated at 39, is mounted upon the free end of the interrupter arm 40, the other end of which is pivoted to the disc 25 and is electrically,

connected therewith. A leaf spring 40 normally urges the contact 39 into engagement with the contact-3S. The particular construction of the interrupter devices carried by the armature is not particularly important but it is extremely desirable that these parts lie around the armature bearing boss 14 so that the inner end of the bearing 14 may.lie immediately adjacent the armature disc 25 as shown in Figure 1. rupter arm 40 is provided with a block 41 which co-operates with the annular cam 42. Cam 42 is disposed around and keyed upon hearing boss 14, the boss being provided with a portion of reduced diameter for the reception of the cam as is clearly illustrated The interin Fi ure 1. It will be understood, of course, that in the particular arrangement shown that when, upon the cooking movement of the armature, arm 41 rides up on the flattened surface of the cam, the contacts are permitted to engage, separation of the contacts being efiected when, u n the recoil of the armature, the block 41 rides out to the position shown in Figure 5.

The annular cam 42 is driven to position upon the boss 14 and is held a ainst rotary movement thereon by a Woodru key 43. In order to provide a means forremoving the cam from the parts when desired, a plu- ,rality of apertures 4444 are drilled'throu h plate 13 to a point immediately behind t e cam. By inserting a suitable tool into the apertures 44, the cam may be driven off, of the boss without injury to either the boss the armature shaft is a yoke 48 comprising a push finger 49. Brojec'ting. forwardly from the yoke are pins 50-50 whereon are mounted rollers 51-51. The comparatively heavy tension springs 52-52 act between the rollers 47 and 51 and normally tend to hold the armature of the magneto in the position illustrated in Figure 5. .In the operation of the machine the push finger 49 is of course, actuated in a well-known manner to cock the armature against the tension of the sprin 52. When the push finger is released, t e springs quickly return the armature toward normal position. During the recoil of the armature, current is generated in the prima winding, the circuit of the primary winding being interrupted near the end of the recoil movement of the armature by the separation of the interrupter contacts to the end that high tension current may be induced in the secondar in a \vell-known'manner.

While I have illustrated the improvements of m invention applied to a magneto of the,

osci ating type,-'1t will be understood that. those features of my invention which enable me to emgleoy exceptionally long armature trunnion creasing the over-all length of the magneto, are equally applicable to rotary magneto constructions.

What I claim is new and desire to secure by Letters Patent is 1.' A magneto comprising a housing and an armature structure disposed therein, the armature being provided with trunnions, inwardly pro'ectin hollow bosses carried by the ends 0 the ousing, the bosses constituting bearings for the trunnions, a distributor spool carried at one end of the armature structure and rotatable therewith, said spool provided with a central opening adapted to embrace the adjacent boss, interrupter contacts at the other end of the armature structure and a cam for operating said contacts, said cam comprising an annulus "disposed around and fixed upon the bearing boss adjacent *said contacts.

2. A magneto comprising a housing and an armature structure provided'with trim-- nions mounted therein, the bearing for one of said trunnions comprisin an inwardly projecting hollow boss carrie by one end of the housing, interrupter contacts carried on that end of the armature structure next adjacent the boss and an annulur cam for opcrating) said contacts, said cam being disposed around and secured upon said boss.

3. A magneto comprising a housi'n and inwardly projecting hollow bearirfg sses carried by the ends of the housing, an armature structure disposed in the housing and having trunnions bearing in said bosses, distributor mechanism disposed around one of said bosses and interrupter. mechanism disposed around theother boss.

4. A magneto comprising a housing, and an armature structure provided with trunnions mounted therein, .the bearing for one of said trunnions comprising an inwardly projecting hollow boss carried by one end of the housing, an interrupter mechanism comprising two relatively movable parts, namely, one part which comprises mterrupter contacts and a part which provides the interrupter operating cam, one of the aforesaid parts being carried on that end sof the armature next adjacent said boss, and the other part comprising an annulus which is fitted around and fixed upon said boss.

In witness whereof, I hereunto subscribe my name this 5 da of A 1920.

OHN STARK. Witn:

A. Loan, P. S. CIIWS. 

